Method and means for supplying current to track sections



July 26; 1932.

G. w. BAUGHMAN METHOD AND MEANS FOR SUPPLYING CURRENT TO TRACK SECTIONS nun Filed Sept. 10. 1951 nun INVENTOR- ATTORNEY- Patented July 26, 1932 unrrso STATES PATENT OFFICE GEORGE W. BA'U'GHMAN, OF P ITTSBURGH PENNSYLVANIA, ASSIGNOR T UNION SWI CH & SIGNAL COMPANY, OF swIssvALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA METHOD ANDMEANS roR'surrLYING CURRENT To TRACK SECTIONS Application filed September 10, 1931. Serial No. 562,094.

I The present invention relates generally to train-control systems, and has more particularly reference to trackway means whereby of a track section is utilized to influence a signal and/or brake valve on the train, it sometimes occurs that the train-carried equipment will: be effectively influenced even though one of therails of the track-section is broken. This is especially true where the rails form the return conductor for a propulsion current for the'train, because in systems of this character impedance bonds span the insulation that separates one track section from another, and the train-control current will therefore at times sneak across from one rail to another. This is clearly a disadvantage because while trafic conditions of adjacent blocks or track sections may be such as to permit unrestricted or but slightly restricted speed of a train through a given track section, yet the presence of a broken rail may constitute a dangerous condition that should be indicated on the train so that the speed of the train may be lessened.

"The main object andfeature of this invention is to devise a system whereby only a train-control current of a character to indicaterestricted'speedcan be impressed on a track section having a broken rail notwithstandingthe existence of non-restrictive traffic conditions inone or more adjacent track sections and notwithstanding the fact that the particular track section is itself clear or unoccupied. V I

lInthe accompanying drawing, the invention is disclosed in a concrete and preferred forin which shows a diagrammatic representation of a track system designed to carry out the above objects and features.

1, 2 and 3 indicate three adjacent track sections, composed oftraffic rails, which sections are separated from each other by' means of insulated jointsd. 5 indicates theusual im- I pedance bonds spanning the insulation. Each track section is provided with a track relay T1, T2 and T--3 respectively, and with a track transformer the secondary 6 of which is bridged across the rails of a section. It is, however, unnecessary to describe the wiring and other elements in connection with all of the track sections since that would be mere repetition, and the description will therefore be confined mainly to the elements associated with section 2, reference being only made to suchelements of the other sections as may be necessary to an understanding of the invention. VR indicates a coding relay which is held energized as long as track relay T-2 is energized, its circuit being from a suitable current source over front contact 7 of T2,

conductor 8 and conductor 9 back to the same cuit to the track-transformer at 10 and closes a circuit through a coding device 14 by way of back contact 15. At the same'tilne it closes a circuit at back contact 16 from coding contact 80, 120 or 180 to primary 13 by way of conductors 17, 18 and 12. It is unnecessary to describe coding devicel i and all of the circuits that control current from contacts 80, 120 and 180; sufiice it to say that contacts 120 and Y180 are responsive to trafiic conditions of one or more track sections in advance, and that 80, 120 and 180 represent meanswhereby difierent codes, or current interrupted or varied a different number of times during a given period, can be impressed on the track section so as to give different indications on a train occupying such section. Of the three codes represented by 80, 120 and 180, the 80 code indication is the most restrictive.

VA indicates a control relay having a circuit from a source of'current Over back contact 19 of coding relay VR wire 20, front contact 21 of track relay T2, wire 22 and wire 23 back to source. It will be seen that when relay VA and track relay T-3 are energized and VR is deenergized a coded cur- I rent can be supplied from a suitable current" source over front contact 24 of T-3, wires 25 and 26, front contact 27 of VA, and wire 28, through either 120 or 180 coding contacts, wire 17,back contact l6,.wires 18 and 12, to primary 13 and backto source; On the other hand, if VA is deenergized, even though T3 is energized, the 120 and 180 codes cannot be applied to the rails of the track section 2 be back .tosource. Each track relay is so designed that it will pickup when; supplied with coded current, i

7 Q Lotus now assume thata trainis-iin section VI, and that section: 2=is unoccupied." Irrthese circumstances track. relay T''1 I and conse quently coding relayVR will become deenergized and wi-ll' close the circuit through VA at back contact 191- As "the train enters section- 2, from section 1, track relay T --2'releases andcoding relay VR becomes deenergi'zediby its circuit being; broken at 7. As

, previously described, this disconnects: at 10 the steady current source from primary 513,. closes at 15 the-' circu-it for the coding device '14and-closes a contact at 16 between wires17 and 18 The deenergization. of track relay T2 also opens: contact 21 thereby rupturing the previously described circuit for control-relay'VA; However, relay" VA has a s'l ower'release than relay VB, so that,'before VA releases, 'VR will have closed back contact 32so'that a circuit isestablished through 'VA from'aE-s-uitablesource of current over back contact 32, over wire 33, front contact 34 of VA, :wires 35 and 36, front contact 37 of T3, wires 38 and 22 to VA. and their by wire 23 back to source. I Should T -3;be in its released position at this time, then the circuit for: VA will be as before except thatfrom wire35 current will flow over back contact 39 and Wire 40 to wire 38, sinceif T3 is released .so will repeater relay 41 be released, and'there fore if contact 37 is open, contact 39 will beclo'sed The resulto-f all'this is that rea lay VA remains energized, and the coded current can flow from either 80, 120 01' 180 depending upon traflic conditions of the section or sectionsin advance. When the train en- ".ters'section 3 from section 2, and 3is not alreadyboccupied, then track relay T3 releases and thereby'deenergizes repeater relay 41, but41 is slowerin its release than VA so that the circuit through VA will be'ruptured before Contact 39 is closed. 'Inthesecircumstances, the. previously described circuit from. -contact31(now closed because T3 is deenergized) through coding contact to pIl:

through section 2, broke one of therails. Un-

der these conditions, track relay T2 would not pick upwhen the train has left section 2, relay VH would remain deenergized and the coding device would continue. to run. Consequently, another train entering section 1 would not be able to energize control relay VA, because although T-1' and VR would release and close contact 19, T'-2 would not be energized and contact 21 would therefore be open; When said other train therefore enters section 2, it'cannot', regardless of traflic conditions in advance, receive'a less restrictive indication than that supplied by coding con tact 80' becausecontact 27 would be open and 29 would be closed. Therefore, assuming T-3 to be energized, coded currentifwould flow from the source over contact 24,. wires 25 and 2.6, to contact 29, over wire 30 130 807 and thence by 17 16, 18 and 12 to primary 13 and .so back to source. Again, if T3 is down, when-the other train enters section 2 under the circumstances recited, the coded current will be from a source over contactBl of T.-3, wire 30, coding contact 80, and over 17 ,1 16,18 and 12 to primary 13 and back to source. Thus with a broken rail in section 2, coded current less restrictive than 80 will not be placed upon the rails of section 2 notwithstanding clear traflic conditions sections ahead and notwithstanding the fact that section 2- is otherwise clear.

Although I have herein shown and described only one form of apparatus embodying my invention, it'iS understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention. 111

Having'thus described my invention, what I' claim is: r

1. A track circuit system 'includingz a track section, circuit means including a1-coding device to supply any one of a plurality i of coded currents to said track section, means controlled by traffic conditions of another section to determine which of the coded currents is to be impressed on the track section,

a track relay for said section which when deenergized starts the coding devicein oper-, ation, and means to prevent a-nyfbut a cer tain coded current from being impressed on V the trackisection if the track relay fails to pick up after being deenergized andbeforebeing shunted by the entry of a train into the track section.

2. A track circuit system including: atrack section, circuit means including a coding device to supply any one of a plurality of coded currents to said track section, means controlled by trafiic conditions of another section to determine which of the coded currents is to be impressed on the track section, a track relay for said section which when deenergized starts the coding device in operation, and a relayto prevent any but a certain coded current from being impressed on the track section if the track relay fails to pick up after being deenergized and before being shunted by the entry of a train into the track section.

3. 'A track circuit system including: a track section, circuit means including a cod ing device to supply any one of a plurality of coded currents to said track section, means controlled by trafiic conditions of another section to determine which of the coded currents is to be impressed on the track section, a trackrelay for said section which when deenergized starts the coding device in operation, and a relay controlling said circuit means and controlled by the track relay of its own section and by the track relay of the section in rear of the first-mentioned track section.

4. A track circuit system including: a track section, circuit means including a coding device to supply any one of a plurality of coded currents to said track section, means controlled by traffic conditions of another section to determine which of the coded currents is to be impressed on the track section, a track relay for said section, a control relay for said circuit means to be energized when the track relay of its own section is energized and the track relay of the section in rear of the first-mentioned track section is deenergized, and a coding relay to be deenergized when the track relay of its own section is deenergized to thereby start the coding device in operation and to maintain the control relay energized.

5. A track circuit system including: a track section, circuit means including a coding device to supply any one of a plurality of coded currents to said track section, means controlled by trafiic conditions of another section to determine which of the coded currents is to be impressed on the track section, a track relay for said section, a control relay for said circuit means to be energized when the track relay of its own section is energized and the track relay of the section in rear of the first-mentioned track section is deenergized, a coding relay to be deenergized when the track relay of its own section is deenergized to thereby start the coding device in operation and to maintain the control relay energized, and means controlled by the track relay of the track section in advance to deenergize the control relay when 

